FLAVR SAVR
Overview Flavr Savr, which is also known as CGN-89564-2, is a genetically modified tomato. Calgene, a company based in California, produced it. Naturally grown tomatoes cannot be allowed to ripen on the vine because they soften and cannot be shipped. Picking them before they have ripened allows them to be shipped, however it prevets the tomatoes from developing all of their natural flavors. This is generally why tomatoes from the supermarket do not have as much flavor. FLAVR SAVRs were genetically engineered for human consumption, so it was submitted to the US Food and Drug Administration (FDA) in 1992. In 1994 it was evaluated to be as safe as tomatoes bred by conventional means. It was also determined that the use of aminoglycoside 3’-phosphotransferase II was safe to use to process the development of new tomato varieties. Flavr Savrs began selling in 1994. However, they were only available until 1997, because production costs were getting too high and Calgene was not profiting. Monsanto Company eventually acquired Flavr Savr. Zeneca began selling a tomato paste made from FLAVR SAVRs in the United Kingdom. However, sales declined drastically a few years later due to the spread of incorrect information regarding genetically modified products. Polygalaturonase (PG) Antisense Lines Polygalaturonase (PG) is a tomato fruit enzyme that has the ability to dissolve the pecting in the cell walls of tomatoes, and it is the cause of fruit softening. Researchers at Calgene attempted to suppress PG accumulation in ripening tomatoes by introducing an antisense copy of the gene that would prevent and reduce the formation of PG. This would allow the ripe tomato to stay firm longer, which would allow it to ripen naturally and last longer. This would even allow for tomato transportation after vine-ripening, which would avoid picking green fruits and artificially ripening them via ethylene treatment. Ethylene treatment gives the tomato its color, but not the full array of flavor. The researchers at Calgene were able to identify and clone a tomato fruit PG gene as well as a way to transform and regenerate tomatoes. Kanamycin-resistant organisms in human and animal guts were studied, and they were found to be so common that they were able to overcome any potential influence of the corresponding genes in engineered crop plants. Furthermore, allergic reactions to the kanamycin-resistance proteins were determined to be highly unlikely. These genes were also added to the construct to produce the PG antisense tomatoes. Calgene began producing tomato plants by inserting the PG antisense DNA construction. The resulting tomato lines only produced about 1% of the PG found in conventional tomatoes. Calgene scientists isolated a gene from ''E. coli ''called kan® and inserted it into a plasmid along with the FLAVR SAVR gene from a tomato. These plasmids were then inserted into a group of tomato cells that were growing in a medium containing an antibiotic. The kan® gene produced APH (3’) II, which made the tomato resistant to the antibiotic. The antibiotic would then kill all the cells that did not receive the plasmid. The researchers were able to use the bacterial gene to identify which cells were genetically transformed. The FLAVR SAVR gene from the tomato was an antisense gene. It coded for a strand of RNA that was the reverse of a strand of RNA that naturally occurs in the tomato. The original RNA strand produces the enzyme polygalactutonase (PG0). PG breaks down the pectin in cell walls of tomatoes during the ripening process, causing the tomato to become soft. The FLAVR SAVR gene binds to PG RNA and the two strands cancel each other out. This prevents PG from accumulating and softening the tomato. Furthermore, the data submitted by Calgene shows that the PG-antisense tomato to be indistinguishable in almost every way from a normally grown tomato. The only difference was that the cell wall pectin degraded much more slower, and when made into a paste, it was much more viscous. Business As Calgene hoped, the FLAVR SAVR tomatoes hit the shelves on May 21, 1994. Although the demand for this product was high and remained high, the business was never profitable because the high production and distribution costs were too high. When it was first introduced, there was controversy and consumer resistance due to public misperceptions about genetically altered crops and mutant veggies. After extensive research by Calgene and the FDA, it was established that the FLAVR SAVR tomato was safe to consume. Zeneca introduced a paste made from FLAVR SAVR tomatoes in the United Kingdom in 1996. More than 1.8 million cans were sold in between 1996 and 1999. The reduced processing costs allowed for lower selling prices. Although the tomato paste was selling fast initially, by 1998 sales declined drastically after a broadcast, which featured Dr. Arpad Pusztai, concluded that feeding rates genetically modified potatoes resulted in biological effects that most likely were caused by the genetic engineering process. Although independent analysis determined that this was wrong information, the genetically modified tomato paste never hit the shelves again.